1. Field of the Invention
The present invention relates to various approaches for processing an ongoing stream of digital samples which, when employed together, are suitable for use in a vestigial-sideband (VSB) digital modulator that derives a 6 MHz bandwidth input signal selectively centered either at 63 MHz (Channel 3), 69 MHz (Channel 4) or 5.38 MHz IF (baseband) for a television receiver and, more particularly, for a compressed digital television receiver or set top box. Related applications filed concurrently herewith are SIN(X)/X COMPENSATION CIRCUITRY Ser. No. 09/382,235; COMPLEX MODULATOR CARRIER SIGNAL GENERATOR Ser. No. 09/382,234; and A VSB DIGITAL MODULATOR Ser. No. 09/382,231.
2. Description of the Prior Art
Reference is made to the article "ATSC Re-modulator System" by Hauge et al., IEEE Transactions on Consumer Electronics, Vol. 44, No. 3, and August 1998. This article discloses a VSB digital re-modulator implementation to interconnect between various digital products (e.g., terrestrial digital broadcasting, satellites, digital cable set top boxes, cable modems, DVD, DVCR, PC's, etc.) and digital TV receivers. Such a VSB digital re-modulator is the digital equivalent to current analog re-modulators found in VCR's and video games.
There is a need for a simple and inexpensive approach to digital re-modulation capable of providing an integrated-circuit (IC) implementation of a VSB digital re-modulator that selectively derives a Channel 3, Channel 4 or baseband signal.